THE EBOLA VIRUS DISEASE:The Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever is a severe condition caused by a virus from the Filoviridae family.Known to be a condition that is transmitted from animals to humans, this virus spreads through direct contact with the bodily fluids of an infected person or animal.
Ebola virus disease (EVD) or Ebola hemorrhagic fever (EHF) is a disease that affects mammals, including humans caused by the Ebola virus. Symptoms typically start two days to three weeks after contracting the virus, with a fever, sore throat, muscle pains, and headaches. Typically nausea, vomiting, and diarrhea follow, along with decreased functioning of the liver and kidneys. At this point, some people begin to have bleeding problems.
Life cycles of the Ebolavirus disease EVD is caused by four of five viruses classified in the genus Ebolavirus, family Filoviridae, order Mononegavirales. These four viruses are Bundibugyo virus (BDBV), Ebola virus (EBOV), Sudan virus (SUDV), Tai Forest virus (TAFV). The fifth virus, Reston virus (RESTV), is not thought to be disease-causing in humans.
According to the WHO (World Health Organisation) this disease can be transmitted from close contact with the blood, secretions, organs or other bodily fluids of infected animals. In humans the disease can be transmitted by the following methods:
- Coming into contact with the blood, secretions, organs or other bodily fluids of an infected person.
- Healthcare workers may contract the disease through transmission as well through contact with infected bodily fluids.
- Handling the meat from infected animals.
- Contact with the bodily fluids of an infected person who has passed away.
The incubation period (or the time between when the actual infection takes place to the time when a person sees symptoms of this condition) for this disease is about one week. After this period a person will commonly see the signs that are considered as ‘early symptoms’.
Once the condition has progressed a person may notice symptoms like:
- Bleeding from the mouth, ears, nose and ears.
- Increased sensitivity to pain on the skin.
- Genital swelling.
- Rashes all over the body.
- And reddening of the roof of the mouth.
Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.
Ebola virus infections can be diagnosed definitively in a laboratory through several types of tests:
- Antibody-capture enzyme-linked immunosorbent assay (ELISA)
- Antigen detection tests
- Serum neutralization test
- Reverse transcriptase polymerase chain reaction (RT-PCR) assay
- Electron microscopy
- Virus isolation by cell culture.
- Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.
- Ebola viruses are contagious, with prevention predominantly involving behavior changes, proper full-body personal protective equipment, and disinfection.
- Techniques to avoid infection involve not contacting infected blood or secretions, including from those who are dead.
- Recommended measures when caring for those who are infected include isolating them, sterilizing equipment, and wearing protective clothing including masks, gloves, gowns and goggles.
- Hand washing is important but can be difficult in areas where there is not even enough water for drinking.
No vaccine is currently available for humans. The most promising candidates are DNA vaccines or vaccines derived from adenoviruses,vesicular stomatitis Indiana virus (VSIV) or filovirus-like particles (VLPs)because these candidates could protect nonhuman primates from ebolavirus-induced disease. DNA vaccines, adenovirus-based vaccines, and VSIV-based vaccines have entered clinical trials.
Ebola viruses are World Health Organization Risk Group 4 pathogens, requiring biosafety level 4-equivalent containment. Laboratory researchers must be properly trained in BSL-4 practices and wear proper personal protective equipment.
No ebolavirus-specific treatment exists.Treatment is primarily supportive in nature and includes minimizing invasive procedures, balancing fluids and electrolytes to counter dehydration, administration of anticoagulants early in infection to prevent or control disseminated intravascular coagulation, administration of procoagulants late in infection to control bleeding, maintaining oxygen levels, pain management, and the use of medications to treat bacterial or fungal secondary infections. Early treatment may increase the chance of survival.